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As we've gotten more device computers have gotten more powerful. Server software has gotten better. HTTP has Keepalive and multiplexing now. Encryption and networking are offloaded to hardware and we have a lot more cores. I would guess a single server can handle thousands of times as many users as it could handle years ago. HAProxy, Netty, Nginx, and others can handle over a million (simple) HTTP requests per second…
Thanks for the info very useful, I didn't realise how unreliable AWS is for database servers. You're correct random unannounced shutdowns of db servers is just not acceptable for critical data. I will be launching a new business based on Postgres soon and the thought of this is terrifying. I'm not keen on the RDS type services or CoLo so this is an unexpected problem I need to overcome. Do you know whether VPS provid…
Really consider how important 100% uptime is though. Google and S3 have gone down multiple times without killing the internet or losing a ton of customers. Plenty of large SaaS providers still use maintenance windows. Heck, GitHub went down today. Not sure if you use ADP but that goes down for a couple days a week!
I know it's not the popular thing to do but you can get much better relative reliability by running a single database per tenant and running a limited number of tenants per VM.